The 37-year-old helped to set up striker Zlatan Ibrahimovic for his goal in the victory which maintained PSG's three-point lead over Lyon at the top of Ligue 1.
Beckham, 37, had started the match on the substitutes bench where he struggled to keep warm in the snowy, freezing conditions.
But he played a key role in the injury-time second goal as his pass with the outside of the boot released Jeremy Menez, who found Zlatan Ibrahimovic for the goal.
Despite the fact he had not played a competitive fixture since December 1, the former England captain's cameo went a long way to suggesting he was not merely a clever marketing ploy, but that - as PSG coach Carlo Ancelotti said in his post-match press conference - "he's a PSG player, period".
It had been almost a month since David Beckham and Paris St-Germain fell into each other's arms, but it was not until late on Sunday night that the mutual infatuation was consummated under the lights at a bitterly cold Parc des Princes.
Beckham, who has joined the Qatari-backed club on a five-month deal, delivered a trademark long pass from his deep midfield position shortly after coming on and stopped a Marseille counter-attack seconds later.
Beckham entered as a substitute for Javier Pastore in the 76th minute, becoming the 400th player to wear a PSG kit and the 27th Englishman to don the jersey of the capital club.
Beckham's first interaction with Zlatan Ibrahimovic saw the league's top scorer misplace a pass in the former's direction, drawing sarcastic whistles from supporters.
Wife Victoria braved the freezing temperatures up in the stands to watch her husband, dubbed Le Spice Boy by some sections of the French media, make another debut for another club.
Her cool exterior in the dusting of snow which swept across the ground was in marked contrast to the boyish enthusiasm of her husband who even patiently gave a touchline interview, translated into French by his questioner, as he watched from the bench.